Manufacturing method of cylindrical battery and winding device of winding core

Abstract

The invention provides a manufacturing method of a cylindrical battery and a winding device of a roll core, the cylindrical battery comprises a shell and the roll core, the manufacturing process of the roll core comprises the following steps: a positive plate, a negative plate and a diaphragm are wound to obtain a first core roll, and the diameter of the first core roll is smaller than the designed diameter of the roll core; obtaining a difference value between the diameter of the first core roll and the designed diameter of the roll core; and if the difference value is larger than the preset threshold value, a coating layer with the adjustable thickness is arranged on the periphery of the first core roll to form the second core roll, the difference value between the diameter of the second core roll and the designed diameter is made to be within the design tolerance range, and the technical problem that the roll core consistency is poor can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery processing, and in particular to a method for manufacturing a cylindrical battery and a winding device for a winding core. Background Art

[0002] Large cylindrical batteries are widely used due to their advantages such as high safety, long life, excellent fast charging performance, good cell consistency and low cost.

[0003] Currently, the core of a large cylindrical battery is made by stacking and winding the positive and negative electrode sheets. Before winding the core, the positive and negative electrode sheets are usually in the form of a whole roll. Within the same positive or negative electrode roll, the thickness of the electrode sheets is uneven. This results in different core diameters even if the electrode sheets are wound to the same length, resulting in poor core consistency. Summary of the Invention

[0004] The present invention provides a method for manufacturing a cylindrical battery and a winding device for a winding core, so as to improve the technical problem of poor consistency of the winding core.

[0005] To achieve the above and other related objectives, the present invention provides a method for manufacturing a cylindrical battery. The cylindrical battery includes a shell and a winding core. The manufacturing process of the winding core includes the following methods:

[0006] Winding the positive electrode sheet, the negative electrode sheet, and the separator to obtain a first core roll, wherein the diameter of the first core roll is smaller than the designed diameter of the roll core;

[0007] Obtaining a difference between the diameter of the first core roll and the design diameter of the roll core;

[0008] If the difference is greater than a preset threshold, a coating layer with adjustable thickness is provided on the periphery of the first core roll to form a second core roll, and the difference between the diameter of the second core roll and the designed diameter is within a design tolerance range.

[0009] In the above technical solution, the core has a preset design diameter and tolerance range. The diameter of the first core roll is smaller than the design diameter of the core. The difference between the diameter of the first core roll and the design diameter of the core is obtained. If the difference is greater than the set threshold value, which is the deviation value between the maximum minimum diameter allowed by the core and the design diameter, a second core roll that meets the design requirements is formed by setting a coating layer with adjustable thickness on the periphery of the first core roll. By compensating the diameter of the first core roll by setting a coating layer with adjustable thickness, the effect of the fluctuation of the thickness of the electrode on the diameter of the core can be offset, thereby improving the consistency of the diameter of the core. The consistent diameter of the core is conducive to the unification of the assembly benchmark in the later stage and improves the assembly yield. The stress distribution in the cylindrical battery with consistent core diameter is more uniform, the difference in fast charging performance is reduced, and the safety performance is improved. Moreover, compared with the solution of improving thickness consistency by optimizing the coating process of the electrode, this solution avoids high-cost equipment modification, has good compatibility with existing equipment, and saves production costs.

[0010] In an example of the manufacturing method of the present invention, the diameter of the first core roll is any one of an average diameter, a maximum diameter, and a minimum diameter of the first core roll.

[0011] In the above technical solution, a suitable diameter reference can be selected according to actual needs, and local measurements can be performed on key risk points, which improves detection efficiency and makes the compensation of the coating layer more accurate.

[0012] In an example of the manufacturing method of the present invention, if the difference is greater than a preset threshold, a coating layer with adjustable thickness is provided on the periphery of the first core roll to form a second core roll, and the difference between the diameter of the second core roll and the design diameter of the core roll is within the design tolerance range.

[0013] Dividing the numerical range between the preset minimum diameter and the design diameter of the first core roll into n threshold intervals, where n is greater than or equal to 2;

[0014] Determine the threshold interval where the first core roll is located according to the threshold interval and the difference;

[0015] A coating layer of corresponding thickness is selected according to the threshold interval where the first core roll is located, so that the difference between the diameter of the second core roll and the designed diameter is within the design tolerance range.

[0016] In the above technical solution, the numerical area is divided into n threshold intervals, and the corresponding thickness of the coating layer is selected according to the threshold interval where the first core roll is located to achieve diameter compensation. When the difference is constant, the more threshold intervals there are, the smaller each interval is, and the higher the accuracy of the compensation amount of the corresponding coating layer, the further improving the consistency of the core diameter.

[0017] In an example of the manufacturing method of the present invention, the method further includes: if the difference is less than or equal to a preset threshold, no covering layer is provided on the outer periphery of the first core roll.

[0018] In the above technical solution, if the difference between the diameter of the first core roll and the design diameter of the core is less than the set threshold, it means that the diameter of the first core roll is within the tolerance range of the design diameter of the core, and the requirement can be met without setting a coating layer.

[0019] In an example of the manufacturing method of the present invention, the difference between the diameter of the second core roll and the designed diameter is made within a design tolerance range by adjusting the number of coating layers and / or the thickness of a single coating layer.

[0020] The above technical solution provides a variety of solutions for adjusting the coating thickness, which can dynamically adjust the thickness differences of different batches of pole pieces, thereby reducing production problems caused by material fluctuations, improving production stability and adaptability, making the coating thickness adjustment method more flexible, and further improving the consistency and accuracy of the core diameter.

[0021] In an example of the manufacturing method of the present invention, the first core roll includes a first adhesive tape for sealing the tail end, and the first adhesive tape is wound on the outer layer of the first core roll along the winding direction of the first core roll.

[0022] In this technical solution, the first tape seals the first core roll, improving its structural stability and reducing the risk of looseness, thereby enhancing core consistency. The first tape also prevents the pole piece or diaphragm from rebounding after winding, maintaining a stable diameter and improving the accuracy of first core roll diameter detection. The first tape fixation does not rely on high-precision equipment, making it compatible with existing production lines and particularly suitable for the high-speed mass production of cylindrical batteries.

[0023] In an example of the manufacturing method of the present invention, the number of winding turns of the first tape is m, where m<2, and the first tape includes a first starting end and a first tail end. Along the winding direction of the first tape, the first tail end is connected to the first starting end or is at a distance L from the first starting end.

[0024] In the above technical solution, the number of turns of the first tape, m < 2, includes two cases: m ≤ 1 and 1 < m < 2. When m ≤ 1, it can achieve the tail sealing function while saving materials and processing time. When 1 < m < 2, the first tape is wound more than one turn, and the first tail end exceeds the first starting end, forming an overlap. This can improve the reliability of the first tape's tail sealing and also minimize the amount of the first tape used, avoiding tape redundancy caused by over-wrapping and reducing costs.

[0025] In an example of the manufacturing method of the present invention, the covering layer is formed by winding a second adhesive tape, and the second adhesive tape includes a second starting end;

[0026] When the second tape is wound in the same direction as the first tape, the second starting end is connected to the first tail end or the distance between them is less than 0.5L;

[0027] When the winding direction of the second tape is opposite to that of the first tape, along the winding direction of the second tape, the distance between the second starting end and the first starting end is greater than or equal to 0 and less than 0.5L.

[0028] In the above technical solution, since the first tape is not wound in a full circle, different layers will be formed on the circumference of the first core roll. By limiting the pasting position of the second starting end of the second tape, the second starting end can be avoided from the overlapping part of the first tape, avoiding the problem of more overlapping layers in some positions and fewer overlapping layers in some positions, improving the uniformity of the second tape diameter compensation amount along the circumference of the first core roll, ensuring the cylindricity of the core, and further improving the consistency of the core diameter.

[0029] In an example of the manufacturing method of the present invention, the second adhesive tape and the first adhesive tape are made of the same material.

[0030] In the above technical solution, the second tape of the same material expands and contracts synchronously with the first tape during battery charging and discharging or in a high-temperature environment, avoiding delamination or stress concentration caused by thermal expansion differences and reducing the risk of core deformation. There is no need to purchase and store different materials for the first tape and the second tape separately, reducing the complexity of supply chain management. The same winding equipment can be adapted to both tapes, reducing equipment modification costs and commissioning time. The initial viscosity and long-term aging characteristics of the same materials are consistent, and the corrosion resistance is consistent, preventing debonding or interfacial peeling over time and improving the mechanical stability of the core. The thickness fluctuation of tapes of the same material is smaller, and the thickness of the coating layer is more uniform after superposition, which further optimizes the final core diameter tolerance.

[0031] In an example of the manufacturing method of the present invention, the first tape and the second tape are insulating tapes.

[0032] In the above technical solution, the insulating tape can effectively isolate the current and prevent the core from short-circuiting during production, transportation and use, thereby improving the safety of cylindrical batteries during processing and use.

[0033] In an example of the manufacturing method of the present invention, the thickness of the first adhesive tape and the second adhesive tape is 15um to 150um.

[0034] In the above technical solution, the insulating tape, with a thickness ranging from 15µm to 150µm, has moderate adhesion, securely securing the end of the core while leaving no adhesive residue when peeled off, keeping the core surface clean. Furthermore, a variety of sizes are available to meet the needs of various scenarios, enhancing the controllability and adjustability of the second tape's compensation for the first core's diameter, further improving the consistency of the core diameter.

[0035] In an example of the manufacturing method of the present invention, before winding the positive electrode sheet, the negative electrode sheet, and the separator to obtain the first core roll, it also includes: baking the rolled positive electrode sheet and the negative electrode sheet so that the moisture content of the positive electrode sheet and the negative electrode sheet meets the set requirements.

[0036] In the above technical solution, residual moisture on the positive and negative electrode sheets after rolling can cause local expansion or contraction of the materials, resulting in thickness fluctuations. Baking the positive and negative electrode sheets can reduce the fluctuations in diameter after the positive and negative electrode sheets are wound to form a core, thereby improving the consistency of the core diameter. Residual moisture can reduce the flexibility of the electrode sheets, causing them to break or wrinkle during winding. Baking the positive and negative electrode sheets can also reduce the winding breakage rate and improve production efficiency. It can also improve the dryness of the core, thereby improving battery performance and safety.

[0037] In an example of the manufacturing method of the present invention, the cylindrical battery further includes a current collecting disk, and the second core roll is fixedly and electrically connected to the current collecting disk and then assembled into the housing.

[0038] In the above technical solution, the fixed electrical connection between the second core roll and the collector disc helps improve the reliability and stability of the electrical connection within the battery, reducing internal resistance and heat generation. Fixing the second core roll to the collector disc before assembly into the housing ensures the structural stability of the core during assembly, prevents core movement, improves assembly efficiency and precision, and further enhances the consistency of the core diameter.

[0039] The present invention also provides a winding device for a core, including a winding assembly for forming a first core roll, and also including: a covering assembly for forming a covering layer on the outer periphery of the first core roll. After the winding assembly forms the first core roll, the covering assembly arranges a covering layer on the outer periphery of the first core roll according to the difference between the diameter of the first core roll and the design diameter of the core to form a second core roll, wherein the difference between the diameter of the second core roll and the design diameter of the core is within the design tolerance range.

[0040] In the above technical solution, the winding assembly generates the first core roll, and the coating assembly dynamically adjusts the coating thickness to control the diameter of the second core roll within the design tolerance range. This solution addresses the pain point of poor core diameter consistency in large cylindrical battery rolls, achieving precise compensation through a two-stage process. The coating assembly only requires adding a low-cost module to the existing winding machine, achieving the designed diameter through a single compensation, reducing equipment modification costs and achieving the effect of improving the consistency of core diameter.

[0041] In an example of the winding device of the present invention, the winding device further includes a diameter measuring device for detecting the diameter of the first core roll.

[0042] In the above technical solution, the diameter measuring device is used to detect the diameter of the first core roll. Determining the diameter of the first core roll is conducive to accurately grading the diameter deviation of the first core roll, and then determining the thickness of the coating layer, thereby realizing accurate determination of the compensation amount for the diameter of the first core roll, and being able to further improve the consistency of the core roll diameter.

[0043] In an example of the winding device of the present invention, the winding device further includes a control system, which is electrically connected to the covering assembly and the diameter measuring device respectively. The control system receives a signal from the diameter measuring device and controls the movement of the covering assembly according to the signal.

[0044] In the above technical solution, the setting of the control system can realize full automation of diameter control, reduce manual intervention, and be beneficial to improving product yield.

[0045] In an example of the winding device of the present invention, the winding device further includes a core conveying platform, which conveys the first core roll to the covering assembly through the diameter measuring device.

[0046] In this technical solution, the core conveyor platform automates the transfer of cores between different process steps, reducing operational errors and time costs during production. The core conveyor platform allows the first core roll to be directly transported to the wrapping assembly after passing through the diameter measuring device, ensuring real-time and accurate measurement data. This allows core diameter measurement to be seamlessly integrated with the subsequent wrapping process, further improving core diameter consistency.

[0047] The manufacturing method of the cylindrical battery of the present invention is conducive to improving the consistency of the core diameter. Since the core has a preset design diameter and tolerance range, and the diameter of the first core roll is smaller than the design diameter of the core. First, the difference between the diameter of the first core roll and the design diameter of the core is obtained. If the difference is greater than the set threshold, that is, the deviation value between the maximum minimum diameter allowed by the core and the design diameter, a second core roll that meets the design requirements is formed by setting a coating layer with adjustable thickness on the periphery of the first core roll. By compensating the diameter of the first core roll by setting a coating layer with adjustable thickness, the influence of the fluctuation of the electrode thickness on the core diameter can be offset, thereby improving the consistency of the core diameter.

[0048] Consistent core diameter facilitates standardized assembly benchmarks in later stages, improving assembly yield. Cylindrical batteries with consistent core diameters achieve more uniform stress distribution, reducing variations in fast-charging performance and improving safety. Furthermore, compared to approaches that improve thickness consistency by optimizing the electrode coating process, this solution avoids costly equipment modifications, is more compatible with existing equipment, and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 This is a flow chart of an example of a method for manufacturing a cylindrical battery according to the present invention;

[0051] Figure 2 Schematic diagram of the structure of an example of the winding device of the present invention;

[0052] Figure 3 This is a schematic structural diagram of a wrapping assembly in an example of a winding device of the present invention.

[0053] Component number description

[0054] 100. Winding assembly; 110. Positive electrode sheet unwinding mechanism; 120. Negative electrode sheet unwinding mechanism; 130. Diaphragm unwinding mechanism; 140. Cutting mechanism; 150. Gluing mechanism; 200. Coating assembly; 210. Coating layer unwinding mechanism; 220. Rotating mechanism; 230. Pressing mechanism; 300. Diameter measuring device; 400. Tab flattening device; 500. Height measuring device; 600. Core conveying platform; 700. Hipot testing device. DETAILED DESCRIPTION

[0055] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless they conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0056] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those in the examples of the present invention may also be used to implement the present invention.

[0057] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0058] See also Figures 1 to 3 The present invention provides a method for manufacturing a cylindrical battery and a winding device for a core to improve the technical problem of poor core consistency.

[0059] In order to achieve the above-mentioned and other related purposes, the present invention provides a method for manufacturing a cylindrical battery. Figure 1 The cylindrical battery includes a shell and a core. The production process of the core includes the following methods:

[0060] S1. Wind the positive electrode sheet, the negative electrode sheet, and the separator to obtain a first core roll, wherein the diameter of the first core roll is smaller than the designed diameter of the roll core.

[0061] The winding of the first core roll is completed by a winding device.

[0062] S2. Obtain a difference between the diameter of the first core roll and the design diameter of the roll core.

[0063] The diameter of the first core roll is obtained by a diameter detection device or manual detection, and the above difference is obtained by calculation.

[0064] S3. If the difference is greater than a preset threshold, a coating layer with adjustable thickness is provided on the periphery of the first core roll to form a second core roll, and the difference between the diameter of the second core roll and the design diameter is within a design tolerance range.

[0065] The threshold is the deviation between the minimum diameter allowed by the core design tolerance and the design diameter. If the difference is greater than the set threshold, the coating device will wrap the outer periphery of the first core roll to obtain a second core roll that meets the design tolerance.

[0066] By compensating the diameter of the first core roll with a coating layer having an adjustable thickness, the effect of fluctuations in the thickness of the pole piece on the diameter of the core roll can be offset, thereby improving the consistency of the core roll diameter. The consistent core roll diameter is conducive to the unification of the later assembly benchmark and improves the assembly yield. The stress distribution in cylindrical batteries with consistent core roll diameter is more uniform, the difference in fast charging performance is reduced, and the safety performance is improved. Moreover, compared with the solution of improving thickness consistency by optimizing the coating process of the pole piece, this solution avoids the high cost of equipment modification, has good compatibility with existing equipment, and saves production costs.

[0067] In an example of the manufacturing method of the present invention, the diameter of the first core roll is any one of an average diameter, a maximum diameter, and a minimum diameter of the first core roll.

[0068] According to actual needs, a suitable diameter reference can be selected, and local measurements can be performed on key risk points to improve detection efficiency and make the compensation of the coating layer more accurate. For example, in some embodiments, there are requirements for the fluctuation amplitude of the core diameter, and the average diameter should be selected as the diameter reference. In other embodiments, when it is necessary to ensure that the final diameter after the coating layer is compensated does not exceed the design upper limit, the maximum diameter should be selected as the diameter reference. In other embodiments, when it is necessary to ensure that the final diameter after the coating layer is adjusted does not fall below the design lower limit, the minimum diameter should be selected as the diameter reference.

[0069] In an example of the manufacturing method of the present invention, if the difference is greater than a preset threshold, a coating layer with adjustable thickness is provided on the periphery of the first core roll to form a second core roll, and the difference between the diameter of the second core roll and the design diameter of the core roll is within the design tolerance range.

[0070] First, the numerical area between the preset minimum diameter and the design diameter of the first core roll is divided into n threshold intervals, where n is greater than or equal to 2. Due to factors such as the uncertainty of the thickness of the pole piece, the first core roll may have different diameters after winding. The preset minimum diameter of the first core roll is the minimum diameter that may appear based on experience. The preset minimum diameter of the first core roll is used as the minimum value of the numerical area, and the design diameter is used as the maximum value of the numerical area to obtain the numerical area. For example, the preset minimum diameter of the first core roll is a, the design diameter is b, and b is greater than a, then the numerical area is any form of [a, b] or (a, b) or (a, b] or [a, b).

[0071] Next, the threshold interval in which the first core roll is located is determined according to the threshold interval and the difference.

[0072] Thirdly, a coating layer of corresponding thickness is selected according to the threshold interval where the first core roll is located, so that the difference between the diameter of the second core roll and the designed diameter is within the design tolerance range.

[0073] The above numerical range is divided into n threshold intervals, and the corresponding thickness of the coating layer is selected according to the threshold interval where the first core roll is located to achieve diameter compensation. When the difference is constant, the more threshold intervals there are, the smaller each interval is, and the higher the accuracy of the compensation amount of the corresponding coating layer is, which can further improve the consistency of the core diameter.

[0074] In an example of the manufacturing method of the present invention, the method further includes: if the difference is less than or equal to a preset threshold, no covering layer is provided on the outer periphery of the first core roll.

[0075] If the difference between the diameter of the first core roll and the design diameter of the core is less than a preset threshold, it means that the diameter of the first core roll is within the tolerance range of the design diameter of the core and the requirement can be met without providing a coating layer.

[0076] In an example of the manufacturing method of the present invention, the difference between the diameter of the second core roll and the designed diameter is made within a design tolerance range by adjusting the number of coating layers and / or the thickness of a single coating layer.

[0077] This embodiment provides multiple coating thickness adjustment schemes, such as by adjusting the number of coating layers, adjusting the thickness of a single coating layer, or combining the two. Multiple coating thickness adjustment schemes can dynamically adjust for thickness differences between different batches of pole pieces, thereby reducing production issues caused by material fluctuations, improving production stability and adaptability, and making coating thickness adjustment more flexible, further improving the consistency and accuracy of the core diameter.

[0078] In an example of the manufacturing method of the present invention, the first core roll includes a first adhesive tape for sealing the tail end, and the first adhesive tape is wound on the outer layer of the first core roll along the winding direction of the first core roll.

[0079] In this embodiment, the first tape seals the first core roll, improving its structural stability and reducing the risk of looseness, thereby enhancing the consistency of the core. The first tape also prevents the pole piece or diaphragm from rebounding after winding, maintaining a stable diameter and improving the accuracy of first core roll diameter detection. The first tape fixation does not rely on high-precision equipment, making it compatible with existing production lines and particularly suitable for the high-speed mass production of cylindrical batteries.

[0080] In an example of the manufacturing method of the present invention, the number of winding turns of the first tape is m, where m<2, and the first tape includes a first starting end and a first tail end. Along the winding direction of the first tape, the first tail end is connected to the first starting end or is at a distance L from the first starting end.

[0081] In this embodiment, the number of turns of the first tape, m < 2, includes two cases: m ≤ 1 and 1 < m < 2. When m ≤ 1, the tape can be wound to achieve a tail seal while also saving materials and processing time. When 1 < m < 2, the first tape is wound more than one turn, and the first tail end exceeds the first starting end, forming an overlap. This improves the reliability of the tail seal provided by the first tape, while also minimizing the amount of the first tape used, avoiding tape redundancy caused by overwrapping and reducing costs.

[0082] Taking into account that when the first tape is not wound in a full circle, different numbers of layers will be formed on the circumference of the first core roll, in an example of the manufacturing method of the present invention, the covering layer is formed by winding the second tape, and the second tape includes a second starting end; when the second tape is wound in the same direction as the first tape, the second starting end is connected to the first tail end or is less than 0.5L away from the first tail end; when the second tape is wound in opposite directions to the first tape, along the winding direction of the second tape, the distance between the second starting end and the first starting end is greater than or equal to 0 and less than 0.5L.

[0083] By limiting the pasting position of the second starting end of the second tape, the second starting end can be avoided from the overlapping part of the first tape, avoiding the problem of more overlapping layers in some positions and fewer overlapping layers in other positions, improving the uniformity of the second tape diameter compensation amount along the circumference of the first core roll, ensuring the cylindricity of the roll core, and further improving the consistency of the roll core diameter.

[0084] In one example of the manufacturing method of the present invention, the second tape and the first tape are made of the same material. The second tape and the first tape of the same material expand and contract synchronously during battery charging and discharging or in a high-temperature environment, avoiding delamination or stress concentration caused by differences in thermal expansion, and reducing the risk of core deformation. There is no need to purchase and store different materials for the first tape and the second tape separately, reducing the complexity of supply chain management. The same winding equipment can be adapted to two types of tapes, reducing equipment modification costs and debugging time. The initial viscosity and long-term aging characteristics of the same materials are consistent, and the corrosion resistance is consistent, which prevents problems of degumming or interface peeling over time and improves the mechanical stability of the core. The thickness fluctuation of tapes of the same material is smaller, and the thickness of the coating layer is more uniform after superposition, so that the final core diameter tolerance is further optimized.

[0085] In an example of the manufacturing method of the present invention, the first tape and the second tape are insulating tapes. The insulating tapes can effectively isolate current and prevent short circuits in the winding core during production, transportation, and use, thereby improving the safety of cylindrical batteries during processing and use.

[0086] In an example of the manufacturing method of the present invention, the thickness of the first and second tapes ranges from 15um to 150um. This is because insulating tapes with a thickness between 15um and 150um have moderate adhesiveness, firmly securing the end of the core while leaving no adhesive residue when peeled off, keeping the core surface clean. Furthermore, a variety of sizes are available to meet the needs of various scenarios, enhancing the controllability and adjustability of the second tape's compensation for the first core's diameter, further improving the consistency of the core diameter.

[0087] Considering that the residual moisture on the positive and negative electrode sheets after rolling will cause local expansion or contraction of the material, resulting in thickness fluctuations. In an example of the manufacturing method of the present invention, before the positive electrode sheet, the negative electrode sheet and the diaphragm are wound to obtain the first core roll, it also includes: baking the positive and negative electrode sheets after rolling so that the moisture content of the positive and negative electrode sheets meet the set requirements. By baking the positive and negative electrode sheets, the fluctuation of the diameter of the positive and negative electrode sheets after winding to form the core can be reduced, and the consistency of the core diameter can be improved. Residual moisture will reduce the flexibility of the electrode sheet, resulting in breakage or wrinkling of the electrode sheet during winding. Baking the positive and negative electrode sheets can also reduce the winding breakage rate and improve production efficiency.

[0088] In one example of the manufacturing method of the present invention, the cylindrical battery further includes a current collecting tray, and the second core roll is fixedly and electrically connected to the current collecting tray before being assembled into the housing. The fixed electrical connection of the second core roll to the current collecting tray improves the reliability and stability of the electrical connection within the battery, reduces internal resistance, and reduces heat generation. The fixed electrical connection of the second core roll to the current collecting tray before assembly into the housing ensures the structural stability of the roll core during assembly, prevents the roll core from moving, improves assembly efficiency and precision, and further improves the consistency of the roll core diameter.

[0089] See also Figure 2 and Figure 3 The present invention also provides a winding device for a core, including a winding assembly 100 for forming a first core roll. The winding assembly 100 includes multiple unwinding mechanisms, multiple cutting mechanisms 140, a gluing mechanism 150, and a rewinding mechanism, which are sequentially arranged along the conveying direction of the positive electrode sheet, negative electrode sheet, and separator. The unwinding mechanisms include a positive electrode sheet unwinding mechanism 110, a negative electrode sheet unwinding mechanism 120, and a separator unwinding mechanism 130. The rewinding mechanisms are used to rewind the positive electrode sheet, negative electrode sheet, and separator and form a first core roll. Each cutting mechanism 140 is used to cut the corresponding positive electrode sheet, negative electrode sheet, and separator before the winding is completed. The gluing mechanism 150 is used to apply a finishing glue to the wound first core roll before the cutting mechanism 140 cuts the positive electrode sheet, negative electrode sheet, and separator. After the cutting mechanism 140 cuts the positive electrode sheet, negative electrode sheet, and separator, the finishing glue is driven to tighten the first core roll until the finishing is completed, thereby obtaining the first core roll.

[0090] See also Figure 2 and Figure 3 , and also includes a covering component 200 for forming a covering layer on the outer periphery of the first core roll. After the winding component 100 forms the first core roll, the covering component 200 sets a covering layer on the outer periphery of the first core roll according to the difference between the diameter of the first core roll and the design diameter of the core to form a second core roll, wherein the difference between the diameter of the second core roll and the design diameter of the core is within the design tolerance range.

[0091] See also Figure 3 The wrapping assembly 200 forms a wrapping layer around the outer circumference of the first core roll, forming a second core roll. The wrapping assembly 200 includes a wrapping layer unwinding mechanism 210, a rotating mechanism 220 for rotating the first core roll, and a clamping mechanism 230 for positioning the first core roll. This ensures tension on the first core roll and ensures winding accuracy for the second core roll. The assembly also includes a cutting mechanism 140 for severing the wrapping layer after winding.

[0092] See also Figure 2 In this embodiment, the winding assembly 100 generates the first core roll, and the coating assembly 200 dynamically adjusts the coating thickness to control the diameter of the second core roll within the design tolerance range. This solution addresses the pain point of poor core diameter consistency for large cylindrical battery rolls, achieving precise compensation through a two-stage process. The coating assembly 200 only requires adding a low-cost module to the existing winding machine, achieving the designed diameter through a single compensation, reducing equipment modification costs and achieving the effect of improving the consistency of core diameter.

[0093] See also Figure 2 In an example of the winding device of the present invention, the winding device further includes a diameter measuring device 300 for detecting the diameter of the first core roll.

[0094] See also Figure 2 The diameter measuring device 300 is used to detect the diameter of the first core roll and measure the diameter of the first core roll. The diameter measuring device 300 includes a laser diameter measuring sensor that can measure the core roll diameter in a non-contact and high-precision manner. The diameter of the battery core roll is graded by adopting the MES (Manufacturing Execution System) and equipment logic judgment. By combining the software system and hardware equipment, the diameter of the first core roll can be accurately graded. Then, the thickness of the coating layer is determined, and the compensation amount for the diameter of the first core roll is accurately determined, which can further improve the consistency of the core roll diameter.

[0095] See also Figure 2Preferably, in this embodiment, three tab flattening devices 400 and three core height measuring devices 500 are sequentially arranged upstream of the diameter measuring device 300. The tab flattening devices 400 are used to shape the tabs. The core height measuring devices 500 are used to detect the height processing quality of the core, thereby improving the consistency of the core.

[0096] See also Figure 2 In this embodiment, a diameter measuring device 300 is further provided after the covering device for detecting the diameter of the second core roll to ensure that the second core roll that meets the quality requirements is obtained.

[0097] See also Figure 2 In this embodiment, after the diameter measuring device 300 for measuring the second core roll, a Hipot test device 700 (High Potential Test Equipment) is provided to test the insulation integrity of the finished core roll to ensure the safety of the core roll.

[0098] See also Figure 2 In an example of the winding device of the present invention, the winding device also includes a control system (not shown in the figure), which is electrically connected to the covering component 200 and the diameter measuring device 300 respectively. The control system receives a signal from the diameter measuring device 300 and controls the movement of the covering component 200 according to the signal.

[0099] See also Figure 2 In one embodiment, after the winding assembly 100 completes the first core roll, it sends a signal to the control system, which records the diameter data. The diameter measuring device 300 measures the diameter of the first core roll and transmits the data to the control system. The control system calculates the required coating thickness based on a preset tolerance range. Based on the calculated results, the control system adjusts the number of coating layers to ensure that the diameter of the second core roll is within the designed tolerance range. This control system allows for fully automated diameter control, reduces manual intervention, and improves product yield.

[0100] See also Figure 2 In an example of the winding device of the present invention, the winding device further includes a core conveying platform 600 , and the core conveying platform 600 conveys the first core roll to the covering component 200 through the diameter measuring device 300 .

[0101] See also Figure 2The core conveying platform 600 includes a conveyor belt (not shown in the figure) and a guide device (not shown in the figure) to ensure the smooth transmission of the core between different process links. It can realize the automated transmission of the core between different process links, reducing the operational errors and time costs in the production process. Through the core conveying platform 600, the first core roll can be directly conveyed to the coating assembly 200 after passing through the diameter measuring device 300, ensuring the real-time and accuracy of the measurement data, so that the diameter measurement of the core is closely connected with the subsequent coating process, which is conducive to further improving the consistency of the core diameter.

[0102] The manufacturing method of the cylindrical battery of the present invention is conducive to improving the consistency of the core diameter. Since the core has a preset design diameter and tolerance range, and the diameter of the first core roll is smaller than the design diameter of the core. First, the difference between the diameter of the first core roll and the design diameter of the core is obtained. If the difference is greater than the set threshold, that is, the minimum deviation value of the design diameter of the core, a second core roll that meets the design requirements is formed by setting a coating layer with adjustable thickness on the periphery of the first core roll. By compensating the diameter of the first core roll by setting a coating layer with adjustable thickness, the influence of the fluctuation of the electrode thickness on the core diameter can be offset, thereby improving the consistency of the core diameter.

[0103] Consistent core diameter facilitates standardized assembly benchmarks in later stages, improving assembly yield. Cylindrical batteries with consistent core diameters achieve more uniform stress distribution, reducing variations in fast-charging performance and improving safety. Furthermore, compared to approaches that improve thickness consistency by optimizing the electrode coating process, this solution avoids costly equipment modifications, is more compatible with existing equipment, and reduces production costs.

[0104] Therefore, the present invention effectively overcomes some practical problems in the prior art and thus has high utilization value and practical significance. The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a cylindrical battery, wherein the cylindrical battery comprises a shell and a winding core, characterized in that: The production process of the roll core includes the following methods: Winding the positive electrode sheet, the negative electrode sheet, and the separator to obtain a first core roll, wherein the diameter of the first core roll is smaller than the designed diameter of the roll core; Obtaining a difference between the diameter of the first core roll and the design diameter of the roll core; If the difference is greater than a preset threshold, a coating layer with adjustable thickness is provided on the periphery of the first core roll to form a second core roll, and the difference between the diameter of the second core roll and the designed diameter is within a design tolerance range.

2. The production method according to claim 1, characterized in that The diameter of the first core roll is any one of an average diameter, a maximum diameter, and a minimum diameter of the first core roll.

3. The production method according to claim 1, characterized in that If the difference is greater than a preset threshold, a coating layer with adjustable thickness is provided on the periphery of the first core roll to form a second core roll, and the difference between the diameter of the second core roll and the design diameter of the roll core is within the design tolerance range. Dividing a numerical range between a preset minimum diameter of the first core roll and the design diameter into n threshold intervals, where n is greater than or equal to 2; determining the threshold interval where the first core roll is located according to the threshold interval and the difference; A coating layer of corresponding thickness is selected according to the threshold interval where the first core roll is located, so that the difference between the diameter of the second core roll and the designed diameter is within a design tolerance range.

4. The production method according to claim 1, characterized in that Also includes: If the difference is less than or equal to the preset threshold, the covering layer is not provided on the outer periphery of the first core roll.

5. The production method according to any one of claims 1 to 4, characterized in that: The difference between the diameter of the second core roll and the designed diameter is made within the design tolerance range by adjusting the number of layers of the coating layer and / or the thickness of a single coating layer.

6. The production method according to claim 1, characterized in that: The first core roll includes a first adhesive tape for sealing the tail end, and the first adhesive tape is wound on the outer layer of the first core roll along the winding direction of the first core roll.

7. The production method according to claim 6, characterized in that: The number of winding turns of the first tape is m, where m<2. The first tape includes a first starting end and a first tail end. Along the winding direction of the first tape, the first tail end is connected to or separated from the first starting end by a distance L.

8. The production method according to claim 7, characterized in that: The covering layer is formed by winding a second adhesive tape, wherein the second adhesive tape includes a second starting end; When the second tape is wound in the same direction as the first tape, the second starting end is connected to the first tail end or is less than 0.5L away from the first tail end; When the winding direction of the second tape is opposite to that of the first tape, along the winding direction of the second tape, the distance between the second starting end and the first starting end is greater than or equal to 0 and less than 0.5L.

9. The production method according to claim 8, characterized in that: The second adhesive tape is made of the same material as the first adhesive tape.

10. The manufacturing method according to claim 8, characterized in that: The first adhesive tape and the second adhesive tape are insulating adhesive tapes.

11. The manufacturing method according to claim 8, characterized in that: The thickness of the first adhesive tape and the second adhesive tape is 15um to 150um.

12. The manufacturing method according to claim 1, characterized in that: Before the positive electrode sheet, the negative electrode sheet and the separator are wound to obtain the first core roll, the method further includes: baking the rolled positive electrode sheet and the negative electrode sheet so that the moisture content of the positive electrode sheet and the negative electrode sheet meets the set requirements.

13. The manufacturing method according to claim 1, characterized in that: The cylindrical battery further includes a current collecting disk, and the second core roll is assembled into the housing after being fixedly and electrically connected to the current collecting disk.

14. A winding device for a core, comprising a winding assembly for forming a first core roll, characterized in that: Also includes: A covering component is provided to form a covering layer on the periphery of the first core roll. After the winding component forms the first core roll, the covering component sets a covering layer on the periphery of the first core roll according to the difference between the diameter of the first core roll and the design diameter of the core to form a second core roll, wherein the difference between the diameter of the second core roll and the design diameter of the core is within the design tolerance range.

15. The winding device according to claim 14, characterized in that The winding device further includes a diameter measuring device for detecting a diameter of the first core roll.

16. The winding device according to claim 15, characterized in that The winding device further includes a control system, which is electrically connected to the covering assembly and the diameter measuring device respectively. The control system receives a signal from the diameter measuring device and controls the movement of the covering assembly according to the signal.

17. The winding device according to claim 15, characterized in that The winding device further includes a core conveying platform, which conveys the first core roll to the covering assembly via the diameter measuring device.

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